Those who believe that one must look to the sea for really bizarre aquatic life forms have no doubt missed the frog mouthed catfish. If ever a freshwater fish were to qualify as a true oddity, something along the lines of a marine anglerfish, it is certainly this Southeast Asian native. In its appearance, movements (“walking” rather than swimming) and ability to vocalize (the sound it makes, “chaca-chaca” has given rise to the Genus’ name), this unusual creature seems to straddle the line between fish and amphibian.

Catfish Heaven
I first came upon the frog mouth catfish in a book translated from Japanese. As I learned upon visiting Japan, catfishes of all types are incredibly popular there – one store I frequented had over 50 tanks of various species! The fact that Prince Akishino (son of Emperor Akihito) studies catfishes has increased public awareness and appreciation of these often over-looked creatures.

Fortunately, I had a number of contacts in Japanese pet stores and public aquariums…this was paradise for me, and I was able to learn a great deal about catfishes that I had not encountered before, including the frog mouth.

Description and Range
The frog mouth catfish is a squat, mainly brownish fish, possessing a huge mouth that gives a square shape to the head. The tiny eyes are nearly invisible, and from the wide head the body tapers sharply. Cutaneous flaps of skin help to break up the body’s outline and add to the camouflage effect as the fish lies on the river bottom waiting for prey.

Native to southern Thailand, Malaysia, Sumatra and Borneo, the frog mouth catfish is not common in the US pet trade but is becoming increasingly available. Best kept by those with some aquarium experience, it is well worth searching for.

A Shy and Sedentary CaptiveAlthough not an active fish, the frog mouth does require quite a bit of room, as it reaches nearly 1 foot in length and is stressed by close confinement. A 30 Long Aquarium is the minimum that I would recommend for a single animal, with a 55 Gallon Aquarium sufficing for a pair or possibly a trio. It spends most of its time hunkered down on the bottom of the aquarium, preferably under cover of some sort, and even at night does not actively hunt for food.

The frog mouth catfish is best kept alone, as it can swallow prey nearly half its own length. Also, it is very prone to stress and does not do well in aquariums housing actively swimming fish.

3 comments

My frogmouth catfish which you have helped me with in the past is behaving strangely, he doesn’t seem sick, but is swimming around more, and staying in the open instead of under plants as usual. Any ideas? Thank you.

As long as he is eating and shows no signs of distress or disease, i wouldn’t worry…is the water quality ok, is it warmer than usual? Are there any fish in the tank that may be spawning? Maybe he’s just feeling happy an dactive these days!

Assuming he is not being bothered by another fish, water quality changes might be behind the fish’s behavior.

Use a test kit to check all parameters – pH and ammonia especially. pH should be around 6 (it tends to drift quickly with frog mouths, please see article for explanation). Frog mouths eat large meals, so ammonia is a constant concern, especially in a smaller tank.

It is best to keep the water on the soft side, and to use a blackwater conditioner, i.e. Marc Weiss Instant Amazon. Check also that your lighting is subdued – a small change such as a new, brighter bulb can make a difference with this sensitive species.

A partial water change would be a good idea, even if all appears in order. Be sure to use a gravel washer each time you do a water change, so that particulate matter is removed along with the water.

About Frank Indiviglio

Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.

Top Aquarium Supplies Categories

Visit Our Sister Blogs

That Fish Blog is designed to help promote knowledge of the pet hobby. If you wish to reference or cite specific information from a blog post, we ask that you provide a link back to the original. The content on That Fish Blog is copyright protected and may not be duplicated without written permission. If you have any questions on this policy, feel free to send us an email at blogs@thatpetplace.com.